A number of prior art devices have been disclosed which relate to safety systems for firearms. For example, in U.S. Pat. No. 4,003,152 (Barker et al) a safety system is described in which a firearm is normally disabled. The firearm is enabled only when a coded signal is transmitted by an authorized person. In U.S. Pat. No. 3,400,393 (Ash), a weapon safety system is disclosed in which an electromagnetic wave transceiver is mounted on a number of weapons. Each weapon is disabled if it is pointed at and detects identical electromagnetic waves transmitted by another weapon with the same transceiver. If no identical electromagnetic wave is received, the weapon is functional. A similar safety system is disclosed in U.S. Pat. No. 2,472,136 (Whitlock). A safety system in which a plurality of weapons can fire only when the weapon trigger is depressed and a specific command signal is received by the weapon is disclosed in U.S. Pat. No. 4,205,589 (Engler et al).